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1.
Rev. bras. reprod. anim ; 47(2): 76-80, abr.-jun. 2023.
Artigo em Inglês | VETINDEX | ID: biblio-1434952

Resumo

The follicular growth waves are directly linked to the fluctuations in plasma gonadotrophins, which are controlled by the hypothalamic GnRH release pattern. Therefore, if the actions of the GnRH are inhibited or blocked, the final stages of the antral follicle growth are suppressed, resulting in an induced anestrus (a.k.a. waveless model). In the human medicine, GnRH agonists or antagonists are broadly used in the control of ovarian disfunctions, as well as in the preparation of women for assisted reproductive cycles. In cattle, a similar effect can be obtained by active immunization against GnRH. This was shown to be a viable strategy, for example, for the control of chronic cases of cystic ovarian disease in oocyte donors. However, on shall take into account the substantial individual variation on the immune response and, consequently, the lack of control of the duration of the anestrus induced. The waveless model is also very useful as a research model, once it controls the potential interference of the endogenous FSH and LH, improving the sensitivity of essays with exogenous hormones and consequently reducing the required number of replicas within studies.(AU)


O padrão de crescimento folicular em ondas está diretamente associado às flutuações nas concentrações plasmáticas de gonadotrofinas, controladas por sua vez pelo padrão de liberação de GnRH hipotalâmico. Desta forma, a inibição ou bloqueio da ação do GnRH suprime as etapas finais do crescimento folicular, resultando em anestro induzido (também chamado modelo waveless). Na medicina humana, agonistas ou antagonistas de GnRH são utilizados tanto no controle de disfunções ovarianas quanto na preparação de pacientes para procedimentos de reprodução assistida. Em bovinos, este efeito pode ser obtido pela imunização ativa contra GnRH, e mostrou-se estratégia viável, por exemplo, no controle de casos crônicos de doença ovariana cística em doadoras de oócitos. Contudo, é importante considerar a grande variação individual na resposta à imunização e consequente impossibilidade de controlar a duração do anestro induzido. O modelo waveless também é de grande utilidade na pesquisa, uma vez que elimina a potencial interferência do FSH e LH endógenos, aumentando a sensibilidade nos ensaios com hormônios exógenos e consequentemente reduzindo o número de réplicas necessárias nos estudos.(AU)


Assuntos
Animais , Bovinos/embriologia , Estruturas Embrionárias/crescimento & desenvolvimento , Fase Folicular , Gonadotropinas/análise
2.
Anim. Reprod. (Online) ; 19(2): e20210041, mai. 2022. tab, ilus
Artigo em Inglês | VETINDEX | ID: biblio-1374253

Resumo

This study aimed to evaluate the efficiency of immunocastration in lambs using testicular morphometry. Thirty lambs were randomly divided into two treatments (subcutaneous administration of 1.0 mL and 0.5 mL of an anti-GnRH vaccine) and a control group (1.0 mL saline solution). The animals were vaccinated at four months of age, received a second dose 30 days later, and were slaughtered 90 days after the first vaccine dose. After slaughter, testicles were collected, and samples were removed for histological processing and evaluation of testicular morphometric parameters. Analysis of variance, Tukey's test, and Kruskal-Wallis test were performed, with a 5% level of significance. There was a reduction in testicular weight, gonadosomatic index, seminiferous tubule diameter, germinal epithelium height, leydigosomatic index, and total tubule length. The total length per testicular gram increased in the immunocastrated group. Intrinsic spermatogenesis yield, Sertoli cell indices, and estimates of sperm and Sertoli cell production were reduced in the immunized groups (P < 0.05). The anti-GnRH vaccine in lambs at doses of 1.0 mL and 0.5 mL is sufficient to promote immunocastration, verified through severe changes in testicular morphometry from animals.(AU)


Assuntos
Testículo/cirurgia , Ovinos , Orquiectomia/instrumentação , Análise do Sêmen/veterinária , Gonadotropinas/imunologia , Análise Multivariada , Análise de Variância , Estatísticas não Paramétricas
3.
Vet. Not. ; 27(1): 85-115, 2021. tab
Artigo em Português | VETINDEX | ID: vti-31087

Resumo

Female dogs neutering is a routine surgery that aims to prevent diseases as well as to help populational control. Urinary incontinence is one of the most significant unwanted consequences following the procedure. Pharmacological treatment is recommended for such case, and alpha-adrenergic and estrogenic drugs have been the most frequent choices reported in literature. Besides, tricyclic antidepressants are also able to control clinical signs. The exact mechanism involved with this condition is not yet fully understood. Estrogen deficiency with a subsequent loss of urethral tonus is believed to trigger clinical signs. However, it is possible that other factors such as gonadotropins and gonadotropin-releasing hormone levels may play a part on this complex mechanism of the post-neutering urinary incontinence.(AU)


Assuntos
Animais , Feminino , Cães , Cães/anatomia & histologia , Uretra , Ovariectomia/veterinária , Gonadotropinas , Estrogênios , Incontinência Urinária , Esterilização
4.
Vet. Not. (Online) ; 27(1): 85-115, 2021. tab
Artigo em Português | VETINDEX | ID: biblio-1502533

Resumo

Female dogs neutering is a routine surgery that aims to prevent diseases as well as to help populational control. Urinary incontinence is one of the most significant unwanted consequences following the procedure. Pharmacological treatment is recommended for such case, and alpha-adrenergic and estrogenic drugs have been the most frequent choices reported in literature. Besides, tricyclic antidepressants are also able to control clinical signs. The exact mechanism involved with this condition is not yet fully understood. Estrogen deficiency with a subsequent loss of urethral tonus is believed to trigger clinical signs. However, it is possible that other factors such as gonadotropins and gonadotropin-releasing hormone levels may play a part on this complex mechanism of the post-neutering urinary incontinence.


Assuntos
Feminino , Animais , Cães , Cães/anatomia & histologia , Estrogênios , Gonadotropinas , Incontinência Urinária , Ovariectomia/veterinária , Uretra , Esterilização
5.
Acta sci. vet. (Impr.) ; 49: Pub. 1823, 2021. tab
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1363830

Resumo

Following the induction of oestrus out of season in small ruminants, low fertility and variations in fertility rates are associated with embryonic losses. One of the main causes of embryonic loss is luteal dysfunction. Gonadotropin Releasing Hormone (GnRH) supports the luteal structure, and increasing progesterone levels may be beneficial in terms of promoting embryonic life. The main objective of the present study was to evaluate the efficacy of GnRH administration following an oestrus induction protocol in the anoestrus season for preventing embryonic loss in goats having failure to conceive during the season. In the study, 106 Damascus goats aged 3-5 years and weighing 45-60 kg were used. The oestrus of 106 goats in the anoestrous group was stimulated with progesterone and pregnant mare serum gonadotropin (PMSG) treatment. Out of breeding season, goats were divided into the 4 following groups: GnRH0 (n = 27), GnRH7 (n = 26), GnRH0+7 (n = 27) and control (n = 26). In each goat, an intravaginal sponge (IS) containing 20 mg of fluorogestone acetate (FGA) was placed into the vagina and left for 9 days. With the withdrawal of the sponge, 550IU PMSG and 125 µg of d-cloprostenol were injected intramuscularly. Oestrus detection was made via teaser bucks for 3 days starting 24 h after withdrawal of the IS. Eighteen bucks known to be fertile were used for breeding. Goats in the oestrus period were mated via natural breeding. The GnRH analogue lecirelin was injected intramuscularly at breeding in the GnRH0 group, on day 7 post-breeding in the GnRH7 group, and both at breeding and on day 7 post-breeding in the GnRH0+7 group. No injections were given to the control group. Blood samples for progesterone measurement were taken by jugular vena puncturing on days 3, 6, 7, 10, 13, 16, and 19 after breeding from 10 randomly chosen goats in all groups. The goats with a level of > 3.5 ng/mL of progesterone on day 21 post-breeding were evaluated as pregnant. Pregnancy was also viewed on day 50 after breeding by real-time ultrasonography (USG) with a 5-7.5 MHz convex probe. The oestrus rate was 96.23% (102/106) in the goats. The rates of onset of oestrus between 36-48 h, 48-60 h and 60 h and beyond were 38.7% (41/106), 21.7% (23/106) and 35.8% (38/106), respectively. The total pregnancy rate was 35.8% (38/106). There were no statistically significant differences (P > 0.05) found for the pregnancy rate, embryonic death rate or progesterone concentration of the groups. However, serum progesterone levels were statistically different in the GnRH7 group compared with the control group (P < 0.05). After synchronisation, various anti-luteolytic strategies can be used to support corpus luteum development and elevate progesterone concentration in the luteal phase to decrease embryonic loss and increase reproductive performance. Therefore, application of GnRH to support the luteal structure and to increase progesterone levels may be beneficial in terms of supporting embryonic life. The results showed that GnRH treatment on the day 7 post-breeding following oestrus induction, including FGA and PMSG, can increase serum progesterone levels in Damascus goats in the anoestrus period. However, following oestrus induction in the anoestrus period, it was seen that GnRH treatment at breeding or on day 7 after breeding did not have any positive effect on embryonic loss or reproductive performance. In conclusion, it was considered that this protocol could be implemented successfully, yielding a 35% pregnancy rate in Damascus goats in the anoestrus period, but embryonic loss must be deeply studied in detail.(AU)


Assuntos
Animais , Feminino , Anestro , Estro/efeitos dos fármacos , Doenças das Cabras/embriologia , Perda do Embrião/veterinária , Gonadotropinas/administração & dosagem , Cabras
6.
Anim. Reprod. ; 18(2): e20210036, 2021. tab, ilus, graf
Artigo em Inglês | VETINDEX | ID: vti-31895

Resumo

The mechanisms by which GnIH regulates the steroid synthesis pathway in duck granulosa cells remain poorly understood. In this study, we measured steroid hormone secretion by ELISA and reproduction-associated gene expression by quantitative real-time Polymerase Chain Reaction (qPCR) in duck granulosa cells treated with different concentrations of GnIH (0, 0.1, 1, 10, and 100 ng/mL) for 24 h. The genome-wide expression profiles of GnIH-treated cells (0 and 10 ng/mL) were evaluated by high-throughput RNA sequencing. Compared with untreated cells, the secretion of the steroid hormones E2, E1, P4, and T was downregulated, with that of E1 and P4 reaching statistical significance (P<0.05); in contrast, the secretion of ACV and INH was significantly upregulated (P<0.05) after treatment with 10 and 100 ng/mL GnIH. The expression of encoding steroidogenic proteins and enzymes genes (STAR, CYP11A1, CYP17A1, CYP19A1, and 3-β-HSD) and encoding gonadotropin receptors genes (FSHR, LHR) were significantly declined (P<0.05) in the 10 and 100 ng/mL GnIH treatments. Transcriptome sequencing identified 348 differentially expressed genes (DEGs), including 253 upregulated and 95 downregulated genes. The DEGs were mainly involved in cell growth and death, immune response, and steroid biosynthesis pathways. We identified four novel DEGs (MROH5, LOC113840576, SDR42E1, and LOC113841457) with key roles in the regulation of steroid hormone biosynthesis. Our study revealed changes in gonadal steroid hormone secretion and steroid biosynthesis pathway-related gene expression in duck granulosa cells under the inhibitory effect of GnIH. These data contribute to our understanding of the molecular and genetic mechanisms underlying reproduction in ducks.(AU)


Assuntos
Animais , Patos/genética , Gonadotropinas/genética , Expressão Gênica , Células da Granulosa
7.
R. bras. Ci. avíc. ; 23(1): eRBCA-2020-1314, 2021. ilus, graf, tab
Artigo em Inglês | VETINDEX | ID: vti-30467

Resumo

This study investigated SNP mutation sites of Gonadotrophin releasing hormone (GnRH) gene in China yellow quail, Beijing white quail and Korean quail through PCR amplification and DNA sequencing technologies. Moreover, polymorphism of GnRH gene and its association with growth traits of quail were analyzed, aiming to get molecular markers associated to growth traits of quail, which could provide references for breeding of new quail species. According to research results, a total of 14 SNP mutation sites of GnRH were detected in China yellow quail, Beijing white quail and Korean quail, which were C71T, C108T, C168T, C178T, A184G, C206T, A209C, C215T, A252G, A279T, C281T, C293G, C339T and C458T. Except that only 2 genotypes were detected for A209C and C281T in China yellow quail and Beijing white quail, 3 genotypes were detected for all of the remaining 12 SNP mutation sites in three quail species. Of the 14 SNP sites, C71T, A209C, C215T, C281T, C293G, C339T and C458T were significantly associated with body weight (p 0.05), C71T, C108T, C168T, C178T, A184G, C206T, C215T, A252G, C293G, C339T and C458T were significantly associated with shank length (p 0.05), C71T, C215T, C293G and C458T were significantly associated with breastbone length (p 0.05), A209C and C281T were significantly associated with shank circumference (p 0.05).(AU)


Assuntos
Animais , Coturnix/crescimento & desenvolvimento , Coturnix/fisiologia , Gonadotropinas , Polimorfismo Genético , Peso Corporal
8.
Rev. bras. ciênc. avic ; 23(1): eRBCA, fev. 2021. ilus, graf, tab
Artigo em Inglês | VETINDEX | ID: biblio-1490841

Resumo

This study investigated SNP mutation sites of Gonadotrophin releasing hormone (GnRH) gene in China yellow quail, Beijing white quail and Korean quail through PCR amplification and DNA sequencing technologies. Moreover, polymorphism of GnRH gene and its association with growth traits of quail were analyzed, aiming to get molecular markers associated to growth traits of quail, which could provide references for breeding of new quail species. According to research results, a total of 14 SNP mutation sites of GnRH were detected in China yellow quail, Beijing white quail and Korean quail, which were C71T, C108T, C168T, C178T, A184G, C206T, A209C, C215T, A252G, A279T, C281T, C293G, C339T and C458T. Except that only 2 genotypes were detected for A209C and C281T in China yellow quail and Beijing white quail, 3 genotypes were detected for all of the remaining 12 SNP mutation sites in three quail species. Of the 14 SNP sites, C71T, A209C, C215T, C281T, C293G, C339T and C458T were significantly associated with body weight (p 0.05), C71T, C108T, C168T, C178T, A184G, C206T, C215T, A252G, C293G, C339T and C458T were significantly associated with shank length (p 0.05), C71T, C215T, C293G and C458T were significantly associated with breastbone length (p 0.05), A209C and C281T were significantly associated with shank circumference (p 0.05).


Assuntos
Animais , Coturnix/crescimento & desenvolvimento , Coturnix/fisiologia , Gonadotropinas , Peso Corporal , Polimorfismo Genético
9.
Anim. Reprod. (Online) ; 15(supl. 1): 868-878, set. 2018. ilus, graf
Artigo em Inglês | VETINDEX | ID: biblio-1461404

Resumo

Puberty is a complex physiological process in females that requires maturation of the reproductive neuroendocrine system and subsequent initiation of highfrequency, episodic release of gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH). Genetics and nutrition are two major factors controlling the timing of puberty in heifers. While nutrient restriction during the juvenile period delays puberty, accelerated rates of body weight gain during this period have been shown to facilitate pubertal development by programming hypothalamic centers that underlie the pubertal process. Among the different metabolic factors, leptin plays a critical role in conveying nutritional information to the neuroendocrine axis and controlling pubertal progression. Because GnRH neurons are devoid of the leptin receptor, leptin’s effects on GnRH neurons must be relayed via an afferent neuronal network. Two neuronal populations located in the arcuate nucleus (ARC) that express the orexigenic peptide neuropeptide Y (NPY), and the anorexigenic peptide alpha melanocyte-stimulating hormone (αMSH), are key components of afferent pathways that convey inhibitory (NPY) and excitatory (αMSH) inputs to GnRH neurons. In addition, ARC neurons expressing kisspeptin, a potent stimulator of GnRH release, are also involved in the nutritional regulation of puberty. Our studies have demonstrated that increased planes of nutrition during juvenile development result in morphological and functional changes in hypothalamic pathways comprising NPY, proopiomelanocortin (POMC), and kisspeptin neurons. Changes included differential expression of NPY, POMC, and Kiss1 in the ARC, and plasticity in the axonal projections to GnRH and kisspeptin neurons. Additionally, increased rates of body weight gain also promoted changes in the pattern of DNA methylation, a key epigenetic mechanism for regulation of gene expression. Finally, our most recent findings suggest that maternal nutrition during gestation can also induce structural and functional changes in hypothalamic neurocircuitries that are likely to persist long after pubertal maturation and influence reproductive performance throughout adulthood in cattle.


Assuntos
Feminino , Animais , Bovinos , Bovinos/anatomia & histologia , Bovinos/embriologia , Leptina , Sistemas Neurossecretores , Gonadotropinas , Hipotálamo , Hormônio Luteinizante
10.
Anim. Reprod. ; 15(supl. 1): 868-878, set. 2018. ilus, graf
Artigo em Inglês | VETINDEX | ID: vti-20071

Resumo

Puberty is a complex physiological process in females that requires maturation of the reproductive neuroendocrine system and subsequent initiation of highfrequency, episodic release of gonadotropin-releasing hormone (GnRH) and luteinizing hormone (LH). Genetics and nutrition are two major factors controlling the timing of puberty in heifers. While nutrient restriction during the juvenile period delays puberty, accelerated rates of body weight gain during this period have been shown to facilitate pubertal development by programming hypothalamic centers that underlie the pubertal process. Among the different metabolic factors, leptin plays a critical role in conveying nutritional information to the neuroendocrine axis and controlling pubertal progression. Because GnRH neurons are devoid of the leptin receptor, leptins effects on GnRH neurons must be relayed via an afferent neuronal network. Two neuronal populations located in the arcuate nucleus (ARC) that express the orexigenic peptide neuropeptide Y (NPY), and the anorexigenic peptide alpha melanocyte-stimulating hormone (αMSH), are key components of afferent pathways that convey inhibitory (NPY) and excitatory (αMSH) inputs to GnRH neurons. In addition, ARC neurons expressing kisspeptin, a potent stimulator of GnRH release, are also involved in the nutritional regulation of puberty. Our studies have demonstrated that increased planes of nutrition during juvenile development result in morphological and functional changes in hypothalamic pathways comprising NPY, proopiomelanocortin (POMC), and kisspeptin neurons. Changes included differential expression of NPY, POMC, and Kiss1 in the ARC, and plasticity in the axonal projections to GnRH and kisspeptin neurons. Additionally, increased rates of body weight gain also promoted changes in the pattern of DNA methylation, a key epigenetic mechanism for regulation of gene expression. Finally, our most recent findings suggest that maternal nutrition during gestation can also induce structural and functional changes in hypothalamic neurocircuitries that are likely to persist long after pubertal maturation and influence reproductive performance throughout adulthood in cattle.(AU)


Assuntos
Animais , Feminino , Bovinos , Sistemas Neurossecretores , Bovinos/anatomia & histologia , Bovinos/embriologia , Leptina , Hipotálamo , Hormônio Luteinizante , Gonadotropinas
11.
Anim. Reprod. (Online) ; 15(supl. 1): 822-842, set. 2018. ilus, graf, tab
Artigo em Inglês | VETINDEX | ID: biblio-1461401

Resumo

In addition to many other functions, the placenta is a source of a vast number of autocrine, paracrine and endocrine factors. However, the spectrum of placental regulatory factors, their concentrations, gestational profiles and roles may differ considerably even between phylogenetically closely related species. Depending on the species, placental regulatory factors of a broad range of molecule classes have been found including (glyco- )proteins, peptides, steroids and prostaglandins. Local placental regulatory factors are especially important for the dialogue between the fetal and the maternal compartment immediately at the feto-maternal borderline and for the control of growth, differentiation and functions of the placenta itself. Moreover, placental hormones in a proper sense may also have effects in more remote targets within the maternal compartment, serving functions such as pregnancy-specific adaptations of maternal circulation, provision of hemotrophe to the fetus or the development and function of the mammary gland. Functions of placental hormones in the fetus proper are less clear but may be especially important before the establishment of a functional fetal endocrine system and near term within the highly species-specific networks of signals preparing and initiating parturition. This review takes a comparative view on the situation in different domestic animals focusing on ruminants and on placental hormones occurring at significant concentrations in the maternal circulation.


Assuntos
Feminino , Animais , Gonadotropinas/análise , Placenta/enzimologia , Placenta/fisiologia , Prenhez/fisiologia
12.
Anim. Reprod. ; 15(supl. 1): 822-842, set. 2018. ilus, graf, tab
Artigo em Inglês | VETINDEX | ID: vti-20069

Resumo

In addition to many other functions, the placenta is a source of a vast number of autocrine, paracrine and endocrine factors. However, the spectrum of placental regulatory factors, their concentrations, gestational profiles and roles may differ considerably even between phylogenetically closely related species. Depending on the species, placental regulatory factors of a broad range of molecule classes have been found including (glyco- )proteins, peptides, steroids and prostaglandins. Local placental regulatory factors are especially important for the dialogue between the fetal and the maternal compartment immediately at the feto-maternal borderline and for the control of growth, differentiation and functions of the placenta itself. Moreover, placental hormones in a proper sense may also have effects in more remote targets within the maternal compartment, serving functions such as pregnancy-specific adaptations of maternal circulation, provision of hemotrophe to the fetus or the development and function of the mammary gland. Functions of placental hormones in the fetus proper are less clear but may be especially important before the establishment of a functional fetal endocrine system and near term within the highly species-specific networks of signals preparing and initiating parturition. This review takes a comparative view on the situation in different domestic animals focusing on ruminants and on placental hormones occurring at significant concentrations in the maternal circulation.(AU)


Assuntos
Animais , Feminino , Placenta/enzimologia , Placenta/fisiologia , Gonadotropinas/análise , Prenhez/fisiologia
13.
R. bras. Reprod. Anim. ; 41(4): 699-709, out.-nov. 2017. tab, graf
Artigo em Português | VETINDEX | ID: vti-18876

Resumo

Objetivou-se a avaliação da efetividade do protocolo de aplicação, em dose única, de gonadotrofinas exógenas (150 UI eCG associado a 100 UI hCG), na indução da atividade ovariana e da ovulação em gatas domésticas, bem como a competência desenvolvimental in vitro e in vivo de embriões felinos produzidos por monta natural, e ainda o efeito da congelação padronizada no desempenho pós-descongelamento de embriões felinos congelados em diferentes fases de desenvolvimento, como modelo experimental para potencial uso em espécies felídeas não domésticas. Foram utilizados três machos e 22 gatas para indução reprodutiva e duas gatas com manifestação natural do cio. Em todas as gatas foram computadas, na superfície ovariana, a presença de corpos lúteos e folículos anovulatórios. Dos animais induzidos e inseminados naturalmente, foram coletados 189 embriões, dos quais: em 27 foi testada a viabilidade de cultivo a fresco; 24 foram transferidos a quatro gatas receptoras, sincronizadas com o mesmo método; e em 21 embriões foi testada a viabilidade de desenvolvimento in vitro, após congelamento com meio (10% glicerol, 0,1mol L-1 sacarose). Conclui-se que o protocolo foi efetivo na produção de embriões felinos, embora haja indícios sugerindo a diminuição da dose de eCG e aumento da dose de hCG. Os embriões produzidos foram viáveis para uso em transferência interespecífica, sendo que 75% (3/4) das fêmeas receptoras ficaram gestantes e 50% levaram a gestação a termo. O protocolo de congelamento reduziu em 51% a taxa de desenvolvimento (8/21), in vitro de embriões felinos e reduziu significativamente (P = 0,01) o número de blastômeros (139,1/161) após 24 horas de cultivo em meio TCM 199 modificado.(AU)


The objective of this study was to evaluate the effectiveness of the single-dose protocol of exogenous gonadotropins (150 IU eCG associated with 100 IU hCG), to induce ovarian activity and ovulation in domestic cats, as well as developmental competence in vitro and in vivo of feline embryos produced by natural mating. The effect of standardized freezing on the post-thawing performance of frozen feline embryos at different stages of development also was evaluated as an experimental model for potential use in non-domestic felid species. For reproductive induction, 3 males and 22 females were used and 2 females with natural estrus. In all females, the presence of luteal bodies and anovulatory follicles were counted on the ovarian surface. Of induced and naturally inseminated animals, 189 embryos were collected, of which: the viability of fresh culture was tested in 27; 24 were transferred to four receiving cats, synchronized with the same method; and in 21 embryos the viability of in vitro development was tested after freezing with medium (10% glycerol, 0.1 mol L-1 sucrose). It was concluded that the protocol was effective in the production of feline embryos, although there are suggestions to decrease the eCG dose and increase the hCG dose. The embryos produced were viable for use in interspecific transfers, with 75% (3/4) of the recipient females becoming pregnant and 50% leading to full term pregnancy. The freezing protocol reduced the rate of in vitro development (8/21), of feline embryos by 51% and significantly reduced the number of blastomers (P = 0.01), after 24 hours of culture in modified TCM 199 medium (139,1/161).(AU)


Assuntos
Animais , Feminino , Gatos , Ovulação , Gonadotropinas/administração & dosagem , Gonadotropinas/efeitos adversos , Desenvolvimento Embrionário , Criopreservação , Criopreservação/veterinária , Eletrocardiografia
14.
Rev. bras. reprod. anim ; 41(4): 699-709, out.-nov. 2017. tab, graf
Artigo em Português | VETINDEX | ID: biblio-1492497

Resumo

Objetivou-se a avaliação da efetividade do protocolo de aplicação, em dose única, de gonadotrofinas exógenas (150 UI eCG associado a 100 UI hCG), na indução da atividade ovariana e da ovulação em gatas domésticas, bem como a competência desenvolvimental in vitro e in vivo de embriões felinos produzidos por monta natural, e ainda o efeito da congelação padronizada no desempenho pós-descongelamento de embriões felinos congelados em diferentes fases de desenvolvimento, como modelo experimental para potencial uso em espécies felídeas não domésticas. Foram utilizados três machos e 22 gatas para indução reprodutiva e duas gatas com manifestação natural do cio. Em todas as gatas foram computadas, na superfície ovariana, a presença de corpos lúteos e folículos anovulatórios. Dos animais induzidos e inseminados naturalmente, foram coletados 189 embriões, dos quais: em 27 foi testada a viabilidade de cultivo a fresco; 24 foram transferidos a quatro gatas receptoras, sincronizadas com o mesmo método; e em 21 embriões foi testada a viabilidade de desenvolvimento in vitro, após congelamento com meio (10% glicerol, 0,1mol L-1 sacarose). Conclui-se que o protocolo foi efetivo na produção de embriões felinos, embora haja indícios sugerindo a diminuição da dose de eCG e aumento da dose de hCG. Os embriões produzidos foram viáveis para uso em transferência interespecífica, sendo que 75% (3/4) das fêmeas receptoras ficaram gestantes e 50% levaram a gestação a termo. O protocolo de congelamento reduziu em 51% a taxa de desenvolvimento (8/21), in vitro de embriões felinos e reduziu significativamente (P = 0,01) o número de blastômeros (139,1/161) após 24 horas de cultivo em meio TCM 199 modificado.


The objective of this study was to evaluate the effectiveness of the single-dose protocol of exogenous gonadotropins (150 IU eCG associated with 100 IU hCG), to induce ovarian activity and ovulation in domestic cats, as well as developmental competence in vitro and in vivo of feline embryos produced by natural mating. The effect of standardized freezing on the post-thawing performance of frozen feline embryos at different stages of development also was evaluated as an experimental model for potential use in non-domestic felid species. For reproductive induction, 3 males and 22 females were used and 2 females with natural estrus. In all females, the presence of luteal bodies and anovulatory follicles were counted on the ovarian surface. Of induced and naturally inseminated animals, 189 embryos were collected, of which: the viability of fresh culture was tested in 27; 24 were transferred to four receiving cats, synchronized with the same method; and in 21 embryos the viability of in vitro development was tested after freezing with medium (10% glycerol, 0.1 mol L-1 sucrose). It was concluded that the protocol was effective in the production of feline embryos, although there are suggestions to decrease the eCG dose and increase the hCG dose. The embryos produced were viable for use in interspecific transfers, with 75% (3/4) of the recipient females becoming pregnant and 50% leading to full term pregnancy. The freezing protocol reduced the rate of in vitro development (8/21), of feline embryos by 51% and significantly reduced the number of blastomers (P = 0.01), after 24 hours of culture in modified TCM 199 medium (139,1/161).


Assuntos
Feminino , Animais , Gatos , Criopreservação , Criopreservação/veterinária , Desenvolvimento Embrionário , Gonadotropinas/administração & dosagem , Gonadotropinas/efeitos adversos , Ovulação , Eletrocardiografia
15.
Rev. bras. reprod. anim ; 41(2): 628-633, Abr.-Jun. 2017. tab
Artigo em Português | VETINDEX | ID: biblio-1492484

Resumo

O consumo de carne ovina no Brasil tem apresentado aumento expressivo, mas sem oferta suficiente para atender a demanda gerada. Visto os entraves reprodutivos na espécie, buscam-se alternativas de manejo que possam incrementar sua eficiência, como a associação de protocolos de sincronização e indução de estro/ovulação. Embora os mais utilizados sejam protocolos a base de prostaglandina F2α (PGF) ou progesterona, a associação com gonadotrofinas tem sido avaliada e demonstra aumento nas taxas reprodutivas.Objetivou-se com este artigo rever os protocolos de sincronização utilizados em ovinos e discutir estratégias para incremento da produção.


The consumption of sheep meat in Brazil has presented a significant increase, but there is no enough product in the market to meet this demand. Considering the reproductive obstacles in the species, alternatives of reproductive management that increase its efficiency, such as the association of synchronization protocols andestrus induction, are sought. Although the most commonly used are prostaglandin or progesterone-basedprotocols, their association with gonadotrophins has been evaluated and allows an increase in reproductive rates. The objective of this article was to review the synchronization protocols used in the species and to discuss strategies to increase production.


Assuntos
Feminino , Animais , Ciclo Estral , Indução da Ovulação , Ovinos , Gonadotropinas , Progesterona/análogos & derivados , Prostaglandinas Sintéticas , Reprodução , Técnicas Reprodutivas
16.
Acta cir. bras. ; 32(2): 140-147, fev. 2017. ilus, graf
Artigo em Inglês | VETINDEX | ID: vti-16340

Resumo

Purpose: To investigate the effect of buserelin on gonadal structure and function in adult male rats. Methods: Twenty-four adult Wistar male rats were divided into three groups: two treated groups and controls. The first and second treated groups received 300 (low dose) and 500 (high dose) µg/kg buserelin, respectively, and the control group received normal saline. All groups were treated subcutaneously for five days. Results: The seminiferous tubular epithelial thickness was significant decreased in the treated groups compared with those in the control. There was a significant increase in apoptotic cell death in high dose treated group compared with low dose treated and control groups. No significant difference in serum testosterone level was observed after one month in the three groups. Conclusion: Buserelin induces apoptotic cell death and decreased diameter and epithelium thickness of seminiferous tubules in the adult rat testes.(AU)


Assuntos
Animais , Masculino , Ratos , Busserrelina/efeitos adversos , Testosterona/análise , Testosterona/sangue , Testosterona/deficiência , Apoptose , Testículo/anatomia & histologia , Hormônio Liberador de Gonadotropina , Ratos Wistar , Gonadotropinas/análise
17.
Anim. Reprod. (Online) ; 14(2): 452-458, Apr.-June.2017. graf, ilus
Artigo em Inglês | VETINDEX | ID: biblio-1461270

Resumo

Gonadotropin inhibitory hormone (GnIH) as a hypothalamic neuropeptide inhibits the synthesis and release of gonadotropins via affecting gonadotropin releasing hormone (GnRH) neurons and could be a key neuropeptide in regulating seasonal breeding in birds. The aim of the present study was to investigate the expression of GnIH in the hypothalamus of male and female chukar partridges (Alectoris chukar) during the breeding and non-breeding seasons. In breeding (May) and non-breeding (January) seasons, the brains of sexually-matured male (n = 10) and female (n = 10) chukar partridges were removed following fixation. Sections (30 μm) were prepared from the entire diencephalon and stained immunohistochemically. GnIH-immunoreactive neurons were primarily found in paraventricular nucleus, and few positive neurons were detected in dorsomedial nucleus. The numbers of GnIH-immunoreactive neurons were significantly lower in the breeding season compared with the non-breeding season in both male and female (P < 0.05). There were no significant differences in the number of GnIH neurons in paraventricular nucleus between the sexes. Gonadal weight and volume in male and female partridges were significantly higher in the breeding season. The results showed that GnIH neurons may partly contribute to the regulation of the seasonal breeding in the chukar partridge.


Assuntos
Animais , Galliformes/anatomia & histologia , Galliformes/crescimento & desenvolvimento , Gonadotropinas/classificação , Gonadotropinas/imunologia
18.
Anim. Reprod. (Online) ; 14(2): 452-458, Apr.-June.2017. graf, ilus
Artigo em Inglês | VETINDEX | ID: vti-15903

Resumo

Gonadotropin inhibitory hormone (GnIH) as a hypothalamic neuropeptide inhibits the synthesis and release of gonadotropins via affecting gonadotropin releasing hormone (GnRH) neurons and could be a key neuropeptide in regulating seasonal breeding in birds. The aim of the present study was to investigate the expression of GnIH in the hypothalamus of male and female chukar partridges (Alectoris chukar) during the breeding and non-breeding seasons. In breeding (May) and non-breeding (January) seasons, the brains of sexually-matured male (n = 10) and female (n = 10) chukar partridges were removed following fixation. Sections (30 μm) were prepared from the entire diencephalon and stained immunohistochemically. GnIH-immunoreactive neurons were primarily found in paraventricular nucleus, and few positive neurons were detected in dorsomedial nucleus. The numbers of GnIH-immunoreactive neurons were significantly lower in the breeding season compared with the non-breeding season in both male and female (P < 0.05). There were no significant differences in the number of GnIH neurons in paraventricular nucleus between the sexes. Gonadal weight and volume in male and female partridges were significantly higher in the breeding season. The results showed that GnIH neurons may partly contribute to the regulation of the seasonal breeding in the chukar partridge.(AU)


Assuntos
Animais , Galliformes/anatomia & histologia , Galliformes/crescimento & desenvolvimento , Gonadotropinas/classificação , Gonadotropinas/imunologia
19.
R. bras. Reprod. Anim. ; 41(1): 86-93, Jan-Mar. 2017.
Artigo em Português | VETINDEX | ID: vti-17164

Resumo

O estudo sobre o controle neuroendócrino da reprodução em teleósteos tem sido importante paracompreender os mecanismos regulatórios da atividade reprodutiva destes animais e possibilitado entender asrazões do bloqueio da reprodução no cativeiro. A reprodução em peixes é modulada por fatores ambientais econtrolada endogenamente por um sistema neuroendócrino, principalmente pelo eixo hipotálamo-hipófisegônadas(H-H-G). Este eixo coordena a síntese de hormônios liberadores, inibidores, gonadotropinas, esteroidesgonadais, regulando assim a reprodução. Este controle endócrino se altera quando espécies migradoras sãotransferidas para o cativeiro, pois neste ambiente confinado, algumas espécies não conseguem eliminar os seusgametas. Neste caso, intervenções hormonais exógenas em diferentes níveis do eixo H-H-G são necessárias paradar continuidade ao processo de maturação gonadal. Esta revisão aborda a fisiologia do eixo H-H-G, com ênfasenos estudos realizados nas espécies neotropicais nacionais e discute disfunções decorrentes do bloqueio dareprodução em animais em cativeiro.(AU)


The study on the neuroendocrine control of teleost reproduction has been important to understand theregulatory mechanisms of reproductive activity of these animals, allowing the understanding the reasons ofreproduction impairment when they are under captivity conditions. The reproduction in fish is modulated byenvironmental factors and endogenously controlled by a neuroendocrine system, mainly by the hypothalamicpituitary-gonadsaxis (H-P-G). This axis coordinates the synthesis of releasing and inhibitory hormones,gonadotropins, gonadal steroids, controlling therefore reproduction. The endocrine control is altered whenmigratory species are transferred to captivity, where some species cannot release their gametes. In this case,exogenous hormones interventions at different levels of the H-P-G axis are necessary to continue the gonadalmaturation process. This review addresses the physiology of the H-P-G axis, emphasizing the studies with thenational neotropical species and discusses dysfunctions resulting from reproduction impairment in captivity.(AU)


Assuntos
Animais , Neuroendocrinologia , Peixes/anatomia & histologia , Peixes/embriologia , Gonadotropinas
20.
Rev. bras. reprod. anim ; 41(1): 86-93, Jan-Mar. 2017.
Artigo em Português | VETINDEX | ID: biblio-1492444

Resumo

O estudo sobre o controle neuroendócrino da reprodução em teleósteos tem sido importante paracompreender os mecanismos regulatórios da atividade reprodutiva destes animais e possibilitado entender asrazões do bloqueio da reprodução no cativeiro. A reprodução em peixes é modulada por fatores ambientais econtrolada endogenamente por um sistema neuroendócrino, principalmente pelo eixo hipotálamo-hipófisegônadas(H-H-G). Este eixo coordena a síntese de hormônios liberadores, inibidores, gonadotropinas, esteroidesgonadais, regulando assim a reprodução. Este controle endócrino se altera quando espécies migradoras sãotransferidas para o cativeiro, pois neste ambiente confinado, algumas espécies não conseguem eliminar os seusgametas. Neste caso, intervenções hormonais exógenas em diferentes níveis do eixo H-H-G são necessárias paradar continuidade ao processo de maturação gonadal. Esta revisão aborda a fisiologia do eixo H-H-G, com ênfasenos estudos realizados nas espécies neotropicais nacionais e discute disfunções decorrentes do bloqueio dareprodução em animais em cativeiro.


The study on the neuroendocrine control of teleost reproduction has been important to understand theregulatory mechanisms of reproductive activity of these animals, allowing the understanding the reasons ofreproduction impairment when they are under captivity conditions. The reproduction in fish is modulated byenvironmental factors and endogenously controlled by a neuroendocrine system, mainly by the hypothalamicpituitary-gonadsaxis (H-P-G). This axis coordinates the synthesis of releasing and inhibitory hormones,gonadotropins, gonadal steroids, controlling therefore reproduction. The endocrine control is altered whenmigratory species are transferred to captivity, where some species cannot release their gametes. In this case,exogenous hormones interventions at different levels of the H-P-G axis are necessary to continue the gonadalmaturation process. This review addresses the physiology of the H-P-G axis, emphasizing the studies with thenational neotropical species and discusses dysfunctions resulting from reproduction impairment in captivity.


Assuntos
Animais , Gonadotropinas , Neuroendocrinologia , Peixes/anatomia & histologia , Peixes/embriologia
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